Conventional circuit breakers are usually placed in operative position either singly or in banks of side-by-side units. These units can contain a handle which protrudes from the circuit breaker or a plurality of switches which are provided within the casing. In either situation, the handle is provided in two extreme positions and a single intermediate position. When the load circuit directly connected to the circuit breaker is overloaded, the circuit blows which causes the operating handle to move from the ON extreme position to the intermediate position as well as interrupting the current conducted to the load circuit. When a number of such circuit breakers are in a group, as they conventionally are, it is difficult to ascertain which circuit breaker has its handle or switch in a blown position, particularly since most circuit breakers are in cellars or similar dimly-lit locations. Additionally, even when the circuit breakers are in brightly lit areas, it is often difficult to determine the particular circuit breaker which has blown. This, of course, is important since, when an overload occurs and the circuit is blown, it must be found and corrected before resetting the circuit breaker by moving the operating handle or switch to the OFF extreme position before it can be moved to the ON position.
U.S. Pat. No. 4,056,816 issued to Raul Guim discloses an illuminated circuit breaker utilizing a light-emitting diode to indicate when the circuit breaker has blown. This diode is provided in a circuit parallel to the main switch of the circuit breaker which includes a resistor in series with the light-emitting diode. However, a difficulty experienced by the device disclosed in the Guim patent is the limitation of the maximum voltage potential which it can withstand. Surge conditions on a public network, or those created artificially by testing laboratories to simulate possible surges in the public network, require these devices to withstand up to 1500 volts, when tripped. Under this tripped condition, any high voltage appearing across the circuit breaker will actually be applied to the load in series with the light-emitting diode and the resistor which is utilized as a voltage reducing element. Since the impedance of the light-emitting diode and the resistor is typically around 25,000 ohms, all of the surge voltage will appear across this resistor during the half-cycle when the light-emitting diode is conducting, since the impedance is several times larger than that of the load.
Thus, the resistor which is utilized in the Guim patent must have a rating of several watts because of its heat dissipation in an environment with virtually no ventilation and lack of heat conduction paths to the outside of the circuit breaker. Additionally, the resistor must be of a sufficient length to withstand the voltage gradient that will be present along the length of the resistor. Because of the space limitations of the circuit breaker, it is absolutely impossible to place such a resistor therewithin, and the conventional resistors which are utilized will crack due to high temperature, arcing or a combination of both.